I remove the arm completely by prying it out by pulling their arm and opening my elbow. From here, just continue with the triangle like usual.

That's not all the trouble we'll get though. Another common defense is to try to do a backdoor escape as the leg passes over. Here is a re-counter that picked up from David Camarillo's new book, as well as Jean-Jacques Five Favorite Finishes video (though he does it from guard).